Archaeologists in Japan have unearthed a 1,900-year-old Chinese mirror that’s not only still intact, but well-preserved enough to still show a faint reflection. City officials in Fukuoka, the capital of the Japanese island where the mirror was found, said such a discovery is extremely rare, according to Japanese national newspaper the Asahi Shimbun.

The bronze mirror was found at the Nakashima archaeological site in Fukuoka’s Hakata Ward. It was made in China during the Later Han Dynasty, between 25 A.D. and 220 A.D., and measures about four and a half inches across. It’s possible that its unusually good condition owes to the region’s humid environment, which could have given it a degree of protection from oxidation, according to the Asahi Shimbun. Inscribed on the surface are the words “chang yi zisun,” which translates as “to benefit future generations forever,” according to the Asahi Shimbun.

“The find site is not a tomb, so the mirror may have been used in religious rites," Hidenori Okamura, a professor of Chinese archaeology at Kyoto University, said, according to the Asahi Shimbun. "The find will also serve as a material for precisely determining the shaky date of the late Yayoi period."

The mirror was excavated earlier this year alongside earthenware representing the middle to late Yayoi pottery culture, which corresponds to between 300 B.C. and 300 A.D., according to the Asahi Shimbun. Yayoi pottery culture succeeded Jōmon culture, a Japanese historical period especially known for its ceramics. Yayoi pottery is known for “clean, functional shapes,” according to the Metropolitan Museum of Art.